When a military unit obsoletes, any existing units are unaffected. Any units of the type in build queues will automatically convert into units of a more advanced type (which will be on their upgrade path), without losing any invested hammers.

When a resource obsoletes, only the ability of a tile with that resource to create the corresponding trade resource for its owning civ is affected. The tile production is not affected, and the civilization can still obtain the trade resource from another, less-advanced civ. If the civilization has any ongoing resource trades where it supplies the resource to another civ, such trades are automatically canceled.

When a building type obsoletes, you can no longer build any buildings of that type. If there is one in any build queue, it is simply removed from the queue; all hammers invested into it are lost. Already completed buildings of that type still exist, and can still serve as the prerequisite to build other units or buildings. Their culture output (), if any, is unchanged. All other effects are lost: obsolete buildings do not generate or multiply science, gold, hammers, etc., they do not add promotions or experience to units, etc.

When a military unit obsoletes, any existing units are unaffected. Any units of the type in build queues will automatically convert into units of a more advanced type (which will be on their upgrade path), without losing any invested production.